1. Field of the Invention:
The invention relates to the construction of a door for a conventional baking and broiling oven, and particularly to a design of a viewing window for the door which will not allow enough heat to escape through the window as might otherwise raise the exterior temperatures of the door to reach unsafe temperature levels.
2. Description of the Prior Art:
For many years the viewing windows of oven doors have comprised a two-pane window pack or subassembly such as is shown in the Mills U.S. Pat. No. 3,021,832. Such a window pack has a pair of glass panes which are spaced apart by a peripheral spacer frame, and the various parts are held together by a continuous clamping and sealing frame. This window pack has a still air space therein for good thermal properties and for sanitary reasons so that the interior surfaces of the glass panes do not become soiled.
As the maximum temperature permitted on the exterior surfaces of the oven door has been reduced in recent years by safety regulating agencies, additional means have been provided to retard the escape of heat through the window. One example is shown in U.S. Pat. No. 3,828,763 of Arthur C. Wilson, which is assigned to the same assignee as is the present invention. Wilson shows a third glass plane on the outer surface of the door which is spaced from the two-pane window pack by a ventilated air channel.
Another design in widespread use is a three-pane window pack that is sealed together in a manner similar to the two-pane window pack.
A principal object of the present invention is to provide a simplified window design for an oven door where the heat loss through the window is reduced over the two-pane and the three-pane window pack designs.
A further object of the present invention is to provide a two-pane window of the class described where there is no direct heat conductive path between the two glass panes.
A further object of the present invention is to provide a window design of the class described with sealing means to prevent the thermal insulation within the door and other air-borne soil from obscuring the view through the window.